Devices are known for detecting the position of a control member on a pad, for example for controlling the position of a pointer on a video screen associated with a computer, with the position of the control member on the pad having the ultimate purpose of selecting a computer function or of changing data contained in the computer. It is important to be able to distinguish between a large number of control points on the pad in order to provide a wide selection range for functions or associated data. When using a magnetic pad associated with a control stylus, it is possible, within limits, to increase the number of distinguishable control points by reducing the active area of the stylus.
When using a touch-sensitive pad the control member is constituted by the finger of an operator. Finger sizes vary between operators and cannot be modified.
French patent specification No. 2 538 581 describes a device for determining the position of a finger between detection areas. However, this device requires a delay to be inserted prior to signal transmission.
An object of the present invention is to provide a device for detecting the position of a control member on a touch-sensitive pad, and having a short response time.